Universal link chain

ABSTRACT

A universal or ball pivot-link chain composed of chain link elements, each such link element possessing at one end a swivel or ball pivot body mounted at the other end of the directly neighboring chain link element. The swivel or ball pivot body comprises two concentric spherical bearing surfaces possessing different radii of curvature, the bearing surface with the smaller radius of curvature being located forwardly of the bearing surface with the largest radius of curvature in the direction of such neighboring link element.

tlnite States atent [1 1 Reist Sept. 11, 1973 UNIVERSAL LINK CIIAIN [75]Inventor: Walter Reist, I-Iinwil, Switzerland [73] Assignee: Ferag AG,Hinwil, Switzerland [22] Filed: Apr. 24, 1972 [2]] Appl. No.: 246,712

[30] Foreign Application Priority Data Apr. 30, 1971 Switzerland 6435/71[52] [1.5. CI 59/78, 59/DIG. 1, 74/501 R, Fl6g/13/20 [58] Field 01Search 59/78.1, 80, 82, 59/78, DIG. 1; 254/134]; 63/4; 74/501 R, 501 P[56] References Cited UNITED STATES PATENTS 1,058,260 4/1913 Prindle59/78 1,327,927 1/1920 Schneider..

1,695,263 12/1928 Jacques ..59/78.1

2/1934 Russell 59/78 3,066,501 12/1962 Charles 59/80 FOREIGN PATENTS ORAPPLICATIONS 410,551 10/1966 Switzerland 59/78 Primary Examiner-CharlesW Lanham Assistant Examiner-Gene P. Crosby AttorneyWerner W. Kleeman 57ABSTRACT A universal or ball pivot-link chain composed of chain linkelements, each such link element possessing at one end a swivel or ballpivot body mounted at the other end of the directly neighboring chainlink element. The swivel or ball pivot body comprises two concentricspherical bearing surfaces possessing different radii of curvature, thebearing surface with the smaller radius of curvature being locatedforwardly of the bearing surface with the largest radius of curvature inthe direction of such neighboring link element.

12 Claims, 7 Drawing Figures PATENTED SEP] 1 I973 SHEET 1 OF 2 PATENTEDSEN I I975 SHEET 2 0F 2 BACKGROUND OF THE INVENTION The presentinvention relates to a new and improved construction of universal orball pivot-link chain arrangement composed of chain link elements whichat one end possess a ball pivot body mounted in the other end of thedirectly neighboring chain link element.

In contrast to link chains employed in the drive and conveying art,wherein the link elements are intercoupled with one another by singleaxis pivots, the universal or ball pivot type of link chains possess thenotable advantage that they can be readily interposed in athree-dimensional arrangement. Thus, such typechains can be guided overdeflecting rolls whose axes extend in skew relationship with respect toone another or they can be guided through guide tubes which, in turn,possess a three dimensional course. Notwithstanding these notableadvantages for the aforementioned fields of use, the universal or ballpivot-link chains heretofore proposed in the art have not found wideacceptance. A number of factors can explain such. Firstly, this is sobecause the ball joint or pivot consisting of the ball pivot body andthe ball socket enclosing such ball pivot body possessdisproportionately large dimensions in radial direction in considerationof proper loading of the material. Moreover, a considerableconstructional expenditure is required for the assembly of universaltype-link chains which adds to the overall cost of the equipment inaddition to the fabrication costs which are already quite considerable.By virtue of these circumstances the use of such type link chains forcarrying out a thrust or pushing action when employing a guide tube isnot absolutely reliable, especially since during a curved course of theguide tube considerable friction forces arise. Therefore, in mostsituations it is not possible to resort to this mode of operation.

This is true for instance for the state-of-the-art type of universal orball pivot-link chain disclosed in Swiss patent 410,551. With this chainconstruction the ball pivot body consists of a spherical or ball segmentembodying a semi-sphere which is mounted in a pivot socket formed at theconfronting end of the neighboring chain link. During pulling of thechain the spherical segment bears against a pivot bowl snapped into thepivot socket when the pivot body is assembled. This mode of assemblyrequires the hollow compartment enclosed by the pivot bowl, as viewed inthe lengthwise direction of the chain, to be deeper than thecorresponding dimension of the pivot body. Hence with regard to thethrust or pushing type of operation of the chain arrangement play ispresent between the chain links which, when overcome during this mode ofoperation, results in a shortening of the chain. When this happens theuniversal or pivot action is of course lost since the joints are onlyconstructed as semi-spherical pivots corresponding to the pivot bodywhich encompasses approximately a semi-sphere. Hence, this type chainconstruction is not proposed to be used for thrust or pushing typeoperations and also is not suitable. Of course in an attempt to counterthese drawbacks it would be possible to construct the pivot bodies ascomplete spheres, in which case then the pivot socket would have to beprovided with an appropriate spherical counter surface. Yet if thismodification is made, it is then at the expense of the contemplatedassembly of the pivot bowl constructed as a spring or snap-type ring.While other modes of assembly would be conceivable if there wereundertaken an appropriate construction of the pivot socket, still theconstruction of the pivot body as a complete or full sphere requiresconsiderable radial dimensions. Moreover, during the thrust mode theradial contact forces in the guide tube, particularly if such is curved,are considerable for such complete spherical pivot joints.

SUMMARY OF THE INVENTION Hence from what has been explained heretoforeit should be apparent that the art is still in need of universal or ballpivot type link chain constructions which are not associated with theaforementioned drawbacks and limitations of the state-of-the-artproposals. It is therefore a primary object of the present invention toprovide a novel construction of universal link chain which is notassociated with the drawbacks and limitations of the prior art asheretofore discussed and which effectively and reliably fulfills theexisting need in the art.

Another and more specific object of the present invention relates to anew and improved universal link chain wherein, while maintaining smallradial dimensions of the ball pivots, not only can be effectively usedduring traction or pulling of the chain but also during pushing orthrust operation thereof, and importantly can be advantageously employedin guide tubes while simultaneously reducing frictional forces.

Yet a further significant object of the present invention relates to anovel construction of ball pivot or universal link chain wherein theindividual link elements incorporate means permitting use of the chainin both a pulling and pushing mode of operation, the individual linkelements are constructed so that they can be easily intercoupled withone another and when desired again disconnected, the fabrication costsof the chain are quite priceworthy, the chain itself requires relativelylittle maintenance and servicing and is extremely reliable in operation.

Now in order to implement these and still further objects of theinvention, which will become more readily apparent as thedescriptionproceeds, the inventive universal link chain, also referred to herein asa ball pivotlink chain, is generally manifested by the features thateach swivel or ball pivot body comprises two concen-- tric sphericalbearing surfaces having different radii of curvature, the bearingsurface possessing the smaller radius of curvature being locatedforwardly or ahead of the bearing surface having the larger radius ofcurvature as viewed in the direction of the neighboring chain link.

The bearing surface with the larger radius of curvature serves for thepulling or traction operation of the chain, and thus in the descriptionto follow will be conveniently referred to as the traction or pullingsurface. In analogous manner the other bearing surface, that is the onewith the smaller radius of curvature and serving for the thrust orpushing operation, will be conveniently referred to hereinafter as thethrust or pushing surface. The traction or pulling surface encloses in aring-like manner the shaft of the associated chain link element; thus itcan possess a relatively large radius of curvature and accordinglypresent a relatively flat surface for the traction load. Consequently,lower specific surface compression prevails since the traction surface,owing to its large radius of curvature, exerts practically no burstingor spreading action. On the other hand, the convex or concave thrust orpushing surface can possess a relatively small radius of curvature sothat the extension of the pivot body in the lengthwise direction of thechain for a convex thrust or pushing surface is equal to the sum of theradii of curvature and for the case of a concave thrust surface thedifference of such radii of curvature. The aforementioned extension ismoreover considerably smaller than in the case of a pivot bodyconstructed as a complete sphere, the extension of which in thelengthwise direction of the chain amounts to approximately twice theradius of curvature of the traction surface. Instead of the equallylarge size radial extension of a pivot body constructed as a completesphere, with the described arrangement there is a reduction in thecorresponding dimension, especially if the swivel or pivot body startingfrom the region of the traction surface tapers in the direction of thethrust surface. The greatest radial extent of the pivot socket islocated at the region of the traction surface. Accordingly, the guidingof the pivot socket in a guide tube is located at the same region andthe thrust surface is displaced forwardly with regard to guiding in thethrust or pushing direction. Consequently, the radial component of thethrust force, in the event that two neighboring chain links during thethrust operation are located at an angle with regard to one another,emanates from the center of the thrust surface, and thus isadvantageously located at a spacing from the location of the support ofthe pivot or ball socket in the guide tube. This again brings about areduction in the surface compression acting between the pivot socket andthe guide tube while simultaneously reducing friction and wear.

The end of the chain link possessing the pivot socket and destined toreceive the tapering swivel or pivot body can be rendered expandable orspreadable through the provision of slots for instance, so that thechain link elements can be formed of one piece and during assemblysimply snapped into one another. In this regard it is also mentionedthechain links preferably possess a rotationally symmetrical shape,simultaneously rendering possible guiding of the chain in tubes or thelike and simplifying fabrication.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be betterunderstood and objects other than those set forth above, will becomeapparent when consideration is given to the following. detaileddescription thereof. Such description makes reference to the annexeddrawings wherein: v

FIG. '1 is a side view, partially in longitudinal section, of auniversal or ball pivot chain arrangement designed according to theteachings of the present invention and guided in a tube;

FIG. 2 is a cross-sectional view through a chain similar to the chainconstruction of FIG. 1, guided in a lengthwise slotted tube, equippedwith entrainment means which have been schematically illustrated;

FIG. 3 illustrates a chain link element of the link chain arrangementdepicted in FIG. 1 at the moment that it is assembled in the directlyneighboring chain link element;

FIG. 4 is a side view, partially in longitudinal section, of a secondembodiment of universal link chain as contemplated by this invention;

FIG. 5 is a side view, again partially in longitudinal section, of athird embodiment of universal link chain which can be guided without anyspecial lubrication in a hollow rail, especially a tube;

FIG. 6 is a longitudinal sectional view through a chain link element ofa modified form of universal link chain; and

FIG. 7 is a cross-sectional view of the link chain arrangement depictedin FIG. 6, taken substantially along the line XI-XI thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now thedrawings, and considering initially the exemplary embodiment ofuniversal or ball pivot-type link chain arrangement as depicted in FIG.1, it will be seen that such is composed of individual chain links orlink elements 1. Each of these chain links or link elements I will beunderstood to comprise a respective swivel or ball pivot body 5, a shaft2 and a counter bearing or support portion 7 intended to receive theswivel or pivot body 5 of the next successive chain link element 1. Theswivel body 5 possesses a substantially spherical-shaped bearing surface10 and a partial spherical bearing surface 8, both of which exhibit acommon center of curvature 3 which, in turn, is located along thelengthwise axis of the chain. Both bearing surfaces 8 and 10 are convex,that is the center of curvature 3 is disposed between both bearingsurfaces 8 and 10. Both of these bearing surfaces 8 and 10 areinterconnected through the agency of a conical surface 9 which possessesa cone angle or angle of opening 4. It is to be observed that theconical surface 9 does not merge tangentially with the bearing surfaceI0, rather with a small circle located, with respect to the center ofcurvature 3, at the same side of the conical surface 9.

A shaft or shaft portion 2 merges with the spherical bearing surface 8,the shape of which is essentially cylindrical. At this essentiallycylindrical shaft portion 2 there merges the counter bearing portion 7.A hollow space or compartment 7a is formed at the counter bearingportion 7, which hollow space is essentially delimited by a concavecounter bearing surface 12, a conical side wall 1 1 and a concavecounter bearing surface 6. This hollow space 7a is constructed so as topossess approximately the opposite shape of the swivel or pivot body 5,with the exception that the opening or cone angle 18 of the conical sidewall 11 is greater than the opening angle 4. The concave counter bearingsurfaces 6 and 12 possess practically the same radii of curvature as thebearing surfaces 8 and 10 and likewise possess the same curvature centerpoint 3. An opening leading towards the outside extends from the hollowcompartment 7a of the counter bearing portion 7, the diameter of whichis greater by a certain amount than that of the shaft portion 2 at thedirect neighborhood of the bearing surface 8. The minimum size of thisdimension depends upon the difference between the opening angles 18 and4 and upon the diameter of the shaft portion and is preferablycalculated such that with the maximum skew between two link elements[i.e., with a deviation of the lengthwise axis of one link element fromthe lengthwise axis of the neighboring element through an angle ofone-half (angle 18 minus angle 4)] no or only a very small play ispresent between the external surface of the shaft 2 and the inner edgeof the opening 18a.

It is readily possible to calculate the minimum radius of curvature ofthe course of the chain for the chain arrangement of FIG. I from thedifference of the cone or opening angles 18 and 4, designated by symbola, as well as from the spacing s between directly successive curvaturecenter points 3. This amounts for instance to the following:

with s 60mm and a 8 about 860mm,

with s 50mm and a 8 about 720mm,

with s 50mm and a 10 about 570mm,

with s 40mm and a 8 about 580mm,

with s 40mm and a 10 about 460mm.

Quite generally the minimum radius of curvature of the course of thechain is proportional to the spacing between directly successivecurvature center points and inversely proportional to the sign of theangular difference between the angle 18 and the angle 4.

Each of the link elements 1 possesses its greatest diameter at thecounter bearing portion 7 which engages about the swivel body 5 of theimmediately next successive chain link element. In FIG. 1 thisapproximately ring-shaped surface has been designated by referencecharacter 16 and is formed to be slightly crowned or bulbous, that is tosay it is convex towards the outside. As a result, there is afforded thepossibility of guiding the chain in a tube or pipe 15, as illustrated,wherein each link element 1, even with a curved course of the tube 15,only contacts the inner wall 17 of the tube along a line disposed in aplane extending transverse to the lengthwise direction of the tube andis spaced from the center of curvature 3 by the distance or spacing a.As a result there is insured for a minimum amount of sliding frictionlosses and owing to the spherical or bulbous shape of the surface 16there is not possible clamping or binding of the link elements 1 in thetube 15.

From what has been previously discussed it should be recognized that theuniversal connection of the link elements of the illustrated chainpossess all degrees of freedom of mobility within certain boundarylimits, however are free of axial play from one chain link element tothe next chain link element. Moreover, the individual link elements canbe rotated about their lengthwise axes with regard to one another.

As best illustrated by referring to FIG. 1, the chain link elements areslotted like pliers in their lengthwise direction. In the present casethere are provided four such slots, of which however only the slot 13 isvisible. The slots 13 each extend in a plane passing through thelengthwise axis of the corresponding chain link element 1 and have awidth which is as small as possible. In the lengthwise direction theslots 13 extend through the entire counter bearing portion 7 and throughthe shaft 2 up to a portion of the swivel or ball pivot body 5. Theseslots 13 serve the purpose of rendering expansible or spreadable thecounter bearing portions 7 so that, as illustrated particularly well inFIG. 3, the swivel body 5 can be introduced without the need of a toolinto the counter bearing portion 7 of the neighboring link element.

Of course, the length of the slots 13 depends upon the properties of thematerial from which the link elements 1 are fabricated and upon thedesired degree of spreading of the four flaps into which the counterbearing portion 7 is subdivided by the slots 13 for the purpose ofintroducing the swivel body 5. I

Now in FIG. 2 there is illustrated a cross-sectional view of a chainarrangement guided in a tube or pipe 15. There is visible in section theshaft 2 with the four slots 13, in front view the counter bearingportion 7 with its peripheral surface 16 which is guided at the innerwall 17 of the tube 15. This tube 15 possesses a longitudinal slot 20through which piercingly extends an entrainment means 21. Theentrainment means 21 can be of any optional design and shape, dependingupon the purposes which it serves. In FIG. 2 it has been intentionallyshown only schematically in order to illustrate that it can be securedat the region of a shaft 2 of a chain link element 1 and extends towardsthe outside of the tube 15. In FIG. 2 entrainment means 21 is secured bymeans of a clamping portion 22 to the shaft 2 and the portion of theentrainment means extending towards the outside of the tube 15 has beendesignated by reference character 23.

As already mentioned, in FIG. 3 there is represented the assembly of twochain link elements 1. If the swivel body 5 of the link element 1 at theright is displaced in the direction of the arrow into the opening 18aand having the angle of opening 14 of the counter bearing portion 7 ofthe link element -1 at the left, then the wedge action produced by theconical surface 9 of the swivel body 5 at the right brings about awidening or spreading of this opening 18a. This is possible owing to theprovision of the slots 13 discussed above. As soon as the inner width ofthe widened opening 18a permits the through passage of the swivel body 5then the counter bearing portion 7 again closes and further displacesthe swivel body 5 until the curvature center point 3' of the bearingportion or surface 10 coincides with the curvature center point 3 of thecounter bearing surface 12. Consequently, the swivel body 5 is held freeof axial play and centered at the counter bearing portion 7.

This joining together or assembly of the link elements which has beenbrought about by a simple pressure action cannot be renderedretroactive, i.e. inadvertently construction which is particularlysuitable for pressure spherical-shaped, however, concave bearing surface25. The bearing surface 8 and the bearing surface 25 possess, as was thecase for the arrangement of FIG. I, the same center of curvature 3.However, in. contrast to FIG. 1, these surfaces are arranged at the sameside of such curvature center point 3.

The hollow space 7a of the counter bearing portion 7 is constructed in adifferent manner for this embodiment. There is provided a substantiallyring-shaped planar shoulder 27 against which bears a truncatedconeshaped pressure portion or component 26 with its small base surface28. The larger "base surface" of this pressure portion 26 is constructedconvex and forms a counter bearing surface 29 for the bearing surface 25of the abutting swivel body 5. This counter bearing surface 29 islikewise spherical and with the curvature center point 3 serving as thecenter.

Moreover, the pressure portion 26 is seated, with as little as possibleradial play in the hollow space 7a of the counter bearing portion 7,upon the shoulder or projection 27. The largest diameter of the pressureportion 26 corresponds in magnitude to the largest diameter of theswivel body so that with the illustrated onepiece construction of chainlink 1 provided with the slots 13 the pressure portion 26 owing to itsconical jacket surface also can be pressed through the opening 180 whilewidening thereof and then into the hollow space or compartment 7a of thecounter bearing portion 7.

The mode of operation of the chain arrangement illustrated in H6. 4corresponds during tension load extensively to that of the chainarrangement of FIG. 1. During pressure load, however, with thisembodiment the specific surface compression between the bearing surface25 and the counter bearing surface 29 is smaller than between thebearing surface and the counter bearing surface 12 of the arrangement ofFIG. 1. Also with this embodiment there is no longitudinal play presentbetween the individual chain links.

It has already been mentioned that the chain arrangement of thisdevelopment is particularly suitable for guiding within hollow rails orthe like, and specifically in the most simple constructional form, in atubular or pipe-shaped member.

Now in FIG. 5 there is illustrated an embodiment of chain arrangementwhich is particularly suitable for this purpose. It correspondsessentially to the embodiment of FIG. 1 so that here only theconstruction thereof which differs from. the chain arrangement of FIG. 1will be considered. This concerns more specifically the external shapeof the counter bearing portion 7. Whereas this external shape wasapproximately conical for the arrangement of FIG. 1, in the arrangementof FIG. 5, it is stepped. Hence it will be seen that an essentiallycylindrical section 30 merges initially with the shaft 2 and thiscylindrical section 30 has a flat end face 31 which confronts the swivelor pivot body 5 of the chain link and which for instance is intended tobe engaged by a sprocket wheel or the like. At the cylindrical section30 there merges a barrel-shaped section 32 onto which there can beslipped or wound a collar 33, for instance formed of an elasticallydeformable plastic material or from a self-lubricating bearing material.The outer surface of this collar or sleeve 33 is likewise barrel-shaped.It therefore provides a safeguard that the tube surrounding the chainarrangement will only be contacted by a chain link along a line. Sincemost plastics possess very small coefficients of friction with regard tometal, the sliding friction losses in the tube are reduced to a minimumwithout additional lubrication. Finally, the collar 33 additionallyfunctions as a security ring which prevents any undesired widening ofthe counter bearing portion 7. This is not possible dur- 8 ing normaloperation of the chain arrangement, as already explained, however withan undesired and irregular kinking or bending of the chain of FIG. 1could lead to jumping out of the swivel body from the counter bearingportion 7. By using the collar 33 this danger is also eliminated.

The embodiment of FlGS. 6 and 7 differs from that of FIG. 5 essentiallyin the features that the counter bearing portion is not elasticallyexpandable or spreadable in order to be able to introduce the swivelbody of the next successive chain link. Accordingly, the counter bearingportion, designated in its entirety by reference character 54, is hereformed of a total of four components. The first component is acylindrical extension or projection 55 having an enlarged diameter andwhich is formed at the shaft 39 of the chain link, this extension orprojection 55 possessing a substantially conical bore 56 which openstowards its free end, and the base of which is rounded in accordancewith the radius of curvature of the bearing surface 36 at the swivelbody 35 of the next following chain link.

This extension or projection 55 is enclosed by a bushing or sleeveconsisting of two halves 57 and 58 and which engage behind theprojection 55 at its end near to the shaft, as illustrated, and at theend removed from the shaft engages over the projection 55 to such anextent that the opening of the bore 56, with the exception of athroughpassage for the shaft 39 of the next successive chain link, iscovered. The inside surfaces of the flaps or tabs 57a and 58a of thebushing halves 57 and 58 respectively and which flaps cover the bore 56are, as best illustrated in F IG. 6, rounded in concave fashion inaccordance with the convex bearing surface 37 of the swivel body 35 ofthe next successive chain link and serve, on the one hand, therefore ascounter bearing surfaces and, on the other hand, to maintain the swivelbody 35 of the next successive chain link free of play at the base ofthe bore 56.

In order that both bushing segments or halves 57 and 58 are supportedover the extension or projection 55 there is drawn over such bushingsegments a sleeve member 59 which, in the event that it should alsosimultaneously serve as a guide body in the manner of the collar 33 ofthe embodiment of FIG. 5, can be formed of plastic or a self-lubricatingbearing material.

While there is shown and described present preferred embodiments of theinvention, it is to be distinctly understood that the invention is notlimited thereto but may be otherwise variously embodied and practicedwithin the scope of the following claims.

Accordingly what is claimed is:

l. A universal link chain arrangement comprising a plurality of chainlink elements, each of said chain link elements possessing at one end aswivel body mounted at the other end of the directly neighboring chainlink element, said swivel body possessing two concentric sphericalbearing surfaces having different radii of curvature, the bearingsurface having the smaller radius of curvature being arranged forwardlyof the bearing surface having the larger radius of curvature in thedirection of such neighboring chain link element.

2. The link chain arrangement as defined in claim 1, wherein the chainlink elements are all essentially of the same shape, a counter bearingportion for each chain link element provided at the other end thereofand capable of receiving the swivel body of the neighboring chain linkelement, said counter bearing portion including means for enablingelastically widening such counter bearing portion.

3. The link chain arrangement as defined in claim 2, wherein each of thechain link elements is formed of one piece.

4. The link chain arrangement as defined in claim 1, wherein bothspherical bearing surfaces of the swivel body are convex.

5. The link chain arrangement as defined in claim 1, wherein thespherical bearing surface having the larger radius of curvature isconvex and the spherical bearing surface having the smaller radius ofcurvature is concave.

6. The link chain arrangement as defined in claim 2, wherein saidcounter bearing portion is provided at least at two diametricallyopposite locations with lengthwise extending slots defining saidenabling means.

7. The link chain arrangement as defined in claim 1, wherein each chainlink element is enclosed by a component at the location of largestdiameter.

8. The link chain arrangement as defined in claim 7,

' other end of each chain link element and composed of a number of partswhich enclose a hollow space intended to receive the swivel body of theneighboring chain link element, this hollow space being delimited bycounter bearing surfaces for the bearing surfaces of the swivel body.

11. The link chain arrangement as defined in claim 1, further includinga hollow guide tube within which travels at least a portion of the linkchain arrangement.

12. The link chain arrangement as defined in claim 11, wherein saidguide tube is slotted in lengthwise direction, and entrainment meanssecured to at least a portion of the link chain arrangement, saidentrainment means extending towards the outside of said guide tube.

1. A universal link chain arrangement comprising a plurality of chainlink elements, each of said chain link elements possessing at one end aswivel body mounted at the other end of the directly neighboring chainlink element, said swivel body possessing two concentric sphericalbearing surfaces having different radii of curvature, the bearingsurface having the smaller radius of curvature being arranged forwardlyof the bearing surface having the larger radius of curvature in thedirection of such neighboring chain link element.
 2. The link chainarrangement as defined in claim 1, wherein the chain link elements areall essentially of the same shape, a counter bearing portion for eachchain link element provided at the other end thereof and capable ofreceiving the swivel body of the neighboring chain link element, saidcounter bearing portion including means for enabling elasticallywidening such counter bearing portion.
 3. The link chain arrangement asdefined in claim 2, wherein each of the chain link elements is formed ofone piece.
 4. The link chain arrangement as defined in claim 1, whereinboth spherical bearing surfaces of the swivel body are convex.
 5. Thelink chain arrangement as defined in claim 1, wherein the sphericalbearing surface having the larger radius of curvature is convex and thespherical bearing surface having the smaller radius of curvature isconcave.
 6. The link chain arrangement as defined in claim 2, whereinsaid counter bearing portion is provided at least at two diametricallyopposite locations with lengthwise extending slots defining saidenabling means.
 7. The link chain arrangement as defined in claim 1,wherein each chain link element is enclosed by a component at thelocation of largest diameter.
 8. The link chain arrangement as definedin claim 7, wherein said component is formed of plastic.
 9. The linkchain arrangement as defined in claim 7, wherein said component isformed of a self-lubricating bearing material.
 10. The link chainarrangement as defined in claim 1, further including a counter bearingportion at the other end of each chain link element and composed of anumber of parts which enclose a hollow space intended to receive theswivel body of the neighboring chain link element, this hollow spacebeing delimited by counter bearing surfaces for the bearing surfaces ofthe swivel body.
 11. The link chain arrangement as defined in claim 1,further including a hollow guide tube within which travels at least aportion of the link chain arrangement.
 12. The link chain arrangement asdefined in claim 11, wherein said guide tube is slotted in lengthwisedirection, and entrainment means secured to at least a portion of thelink chain arrangement, said entrainment means extending towards theoutside of said guide tube.